A descriptive cross-sectional observational study was conducted using an anonymous electronic survey that was not validated (Google Doc® questionnaire). The survey was sent weekly to members of the Spanish Society of Pediatric Intensive Care from April 10, 2023, to May 21, 2023. Completed questionnaires were later analyzed.

The questions were focused on the participants’ workplace, years of experience, use or non-use of HFNC, justification and expectations regarding its application, starting point within each center, clinical criteria for indication, existence of clinical guidelines, evaluation during its use, and criteria and mode of withdrawal. Descriptive analysis of the responses was performed using SPSS® 19 for Windows. The questions and possible responses are described in the Supplementary material 1.

This study shows that most of Spanish pediatric intensivists have access to HFNC in their clinical practice. The use of this therapy, which can also be initiated in other hospital departments, does not typically require mandatory admission to the Pediatric Intensive Care Unit (PICU). HFNC is applied in multiple clinical conditions, with neuromuscular disease being the most common contraindication. Comfort and its impact on reducing the need for therapeutic escalation are among the common reasons for its indication. However, there are still debates about its objective benefits and the potential associated costs. Furthermore, the existence of clinical guidelines for the initiation of HFNC is not widespread, and individualization based on clinical criteria is prioritized when discontinuing the therapy.

Compared to other previously published surveys on HFNC in the context of critically ill children, the number of respondents in this study was high.1–9 At the time of writing this text, the Spanish Society of Pediatric Intensive Care (SECIP) had 588 members, and 176 Spanish intensivists participated in the survey. Participants whose clinical work is not carried out in Spain were excluded to focus the observations on our specific context. As reflected in the results, a large majority of Spanish pediatric intensivists seem to have access to HFNC in their services. Only one out of ten respondents reported not having access to HFNC, and the reasons for this include the absence of evidence, potential delay of other therapies, or high costs.8–12

The profile of the participants reveals an average experience of over four years and a strong affiliation with university hospitals. It is noteworthy that the surveyed participants work in departments with around ten beds and an estimated annual admission rate exceeding three hundred in more than half of the participants. These combined aspects are of particular interest as they undoubtedly reflect the opinions of professionals with significant clinical experience.

It is observed that HFNC can be initiated beyond the Pediatric Intensive Care Unit (PICU). Almost two-thirds of the participants reported that pediatric emergency services in their centers have and use this therapy.13,14 However, this does not necessarily require admission to the PICU.15 We did not ask about the HNFC system used in each center. This could influence the possibility of initiating it beyond PICU. It is likely that the indication for HFNC aims to reduce the likelihood of admission to intensive care units.8 This particular aspect was not addressed in this study.

Considering the HFNC mechanism of action, there is observed disparity in criteria. This variability is simply a reflection of the different theoretical foundations that support this clinical approach and justify the range of possible indications. When asked about its superiority over low-flow nasal cannula, comfort, and the potential to limit therapeutic escalation are identified as key factors. It is worth noting that both considerations are often made with the understanding that current evidence is limited. In this regard, clinical experience and individualization may play a crucial role.

When asked about its value compared to non-invasive ventilation, it is observed that at least half of the participants do not consider it superior. Comfort is the main reason for its indication, while responses indicating a real clinical benefit of HFNC over non-invasive ventilation are in the minority. Participants, through their responses, reflect that HFNC is not an alternative ventilation modality to non-invasive ventilation (the philosophy does not seem to be “either/or”).16 Understanding its limitations, HFNC is presented as a therapeutic possibility for selected patients.7

Thus, when asked about the possible indications of HFNC, acute bronchiolitis,17 post-extubation support,18 pneumonia, and bronchospasm19,20 are clinical scenarios in which HFNC is applicable.4–21 In the adult population, there are studies with both positive and negative results, while in the pediatric population, objective data appears to be limited and inconsistent.22–24 Evaluating indications from the other perspective, namely pure contraindications, it is interesting to observe that HFNC loses relevance in neuromuscular diseases or airway defects. While indications are broad and subject to variability, contraindications tend to be clearer.25

Regarding the existence of clinical guidelines, these have often been developed in collaboration with the nursing service, which is logical considering that the success of various respiratory therapies relies heavily on the work of these professionals. The absence of clinical guidelines for HFNC may contribute to variability and, at the same time, place greater importance on the clinician’s judgment. In the absence of protocols, clinical expertise and experience come into play. However, the presence of guidelines does not seem to be a differentiating factor in determining the signs used to initiate HFNC (as shown in Figs. 3 and 4).

Regarding the prescribed flow rate, it can be affirmed that weight is the most commonly used objective data. This is accompanied by a prevalent protocolized assessment that is usually not followed by post-treatment blood gas analysis. Additionally, multiple clinical criteria are used to evaluate the response (Fig. 5), and it is accompanied by an individual and strict assessment of oxygen requirements. In fact, one in three participants sets the upper limit of tolerable inspired fraction of oxygen at 50% to assess the need for HFNC substitution. These facts are of particular interest since one of the main concerns associated with the use of HFNC is the potential delay in other respiratory interventions.26 Overall, it seems that once the therapy is initiated, frequent clinical monitoring is not only common but also aims to accurately assess the likelihood of non-response.27,28 Finally, during HFNC withdrawal, different methods are prioritized based on clinical judgment. Once again, individualization and experience play a crucial role. This aspect has been described by other authors and, as previously mentioned, appears to be a common approach in clinical practice with this therapy.

This study has significant limitations. Clinical data related to the use of HFNC are not described, only opinions based on clinical experience are presented. Additionally, selection bias may have occurred as those with a more favorable view towards the use of this therapy may have been more likely to respond. All of these factors make it challenging to draw conclusions about the effectiveness of HFNC and only allow for the formulation of working hypotheses.

In summary, it can be observed that most of Spanish pediatric intensivists have access to and use HFNC in their patients. The use and withdrawal of HFNC are primarily based on clinical experience and observation. However, those who use HFNC are aware of its limitations and the lack of evidence in some cases. Therefore, it is of great interest, based on studies like this, to consider the development of both single-center and multicenter studies that can elucidate the reasons and purpose of this therapy in the context of critically ill children.

AGS and AMV designed the web questionary. AGS analyzed the data. AMV co-wrote and corrected it. AGS and AMV coordinated the work. VMiA acts as an internal reviewer. All authors read and approved the final manuscript.